After one too many nights lying awake wondering if he had remembered to close the garage door, Bryan decided to reengineer his automatic door opener. He attached a detector switch to the opener drive rail, which is engaged by the drive shuttle as the door arrives at the fully open position. He wired the switch to a delay timer that begins its count when the switch is closed. When the timing period clocks out, the timer's normally open dry contacts signal the opener to close the door.
Hands-free Garage Door Closer Parts List
Allied Part #
Delay-on make timer relay 120V ac
Octal relay socket
Unidirectional hinge roller switch
6-32 aluminum male-female stand-offs
Conductor 120V ac power vord
Additional parts required: Delay-on make timer relay 24V dc; 24V dc power supply; crimp terminals; small lengths of two conductor wire.
Engineers at the University of San Diego’s Jacobs School of Engineering have designed biobatteries on commercial tattoo paper, with an anode and cathode screen-printed on and modified to harvest energy from lactate in a person’s sweat.
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